1. Field of the Invention
The present disclosure relates to a scroll compressor.
2. Description of the Related Art
Scroll compressor may include a fixed scroll having a fixed wrap and a orbiting scroll having a orbiting wrap. The scroll compressor provides a method of inhaling and compressing refrigerant through a continuous volume change of the compression chamber formed between the fixed wrap and the orbiting wrap while the orbiting scroll performs a orbiting movement on the fixed scroll.
Furthermore, the scroll compressor continuously performs inhalation, compression and discharge, and thus has excellent characteristics in the aspect of vibration and noise generated during its operational process compared to other types of compressors.
In a scroll compressor, the behavior characteristic is determined by its type of the fixed wrap and orbiting wrap. The fixed wrap and orbiting wrap may have an arbitrary shape, but typically have an involute curved shape that can be easily processed. The involute curve denotes a curve corresponding to a trajectory drawn by a cross section of thread when unloosing thread wound around a base circle having an arbitrary radius. When using such an involute curve, the capacity change rate is constant because a thickness of the wrap is constant and thus the number of turns should be increased to obtain a sufficient level of compression ratio, but it may also increase the size of the compressor.
On the other hand, the orbiting scroll is typically formed with a disk shaped end plate and the orbiting wrap at the side of the end plate. Furthermore, a boss portion is formed at a rear surface on which the orbiting wrap is not formed and connected to a rotation shaft for orbiting the orbiting scroll. Such a shape may form a orbiting wrap over a substantially overall area of the end plate, thereby decreasing a diameter of the end plate portion for obtaining the same compression ratio. However, on the contrary, the operating point to which a repulsive force of refrigerant is applied and the operating point to which a reaction force for cancelling out the repulsive force is applied are separated from each other in an axial direction, thereby causing a problem of increasing vibration or noise while the orbiting scroll is tilted during the operational process.
As a method for solving such problems, there has been disclosed a so-called shaft penetration scroll compressor which is a type that a position at which the rotation shaft and the orbiting scroll are combined with each other is formed on the same surface as the orbiting wrap. In such a type of compressor, the operating point of a repulsive force and the operating point of the reaction force are applied at the same position, thereby solving a problem that the orbiting scroll is inclined. However, when the rotation shaft is extended to a orbiting wrap portion in such a manner, an end portion of the rotation shaft is located at a central portion of the orbiting wrap, and accordingly, an intentional compression ratio can be obtained only when increasing the diameter of the end plate. As a result, it may increase the size of the compressor.
However, in case of a shaft penetration scroll compressor as described above, a suction port is eccentrically formed with respect to the center of the rotation shaft as illustrated in the drawing, and thus a gas force is eccentrically exerted and due to this there has been a problem of causing tilting due to the eccentricity of the gas force.